1. Field of the Invention
The present invention relates to a sheet cutting device for cutting a sheet material by a stationary blade and a movable blade after performing printing on the sheet material such as roll paper, and to a printer including the sheet cutting device.
2. Description of the Related Art
Conventionally, as a printer which performs printing on a sheet material in a form of roll paper, there exist a printing device for performing printing on the sheet material sandwiched between a print head and a platen roller, and a printer including a sheet cutting device for cutting the sheet material on which the printing has been performed by the printing device. As the sheet cutting device included in the printer of this type, there is known a sheet cutting device in which a movable blade moves with respect to a stationary blade, thereby cutting a sheet material.
In the related art sheet cutting device, when the sheet material is being cut, due to paper jam, the movable blade is disabled in some cases. In this case, it is necessary that the sheet material being an obstacle for an operation of the movable blade be removed. In order to achieve this, various structures are adopted, for separating the stationary blade and the movable blade from each other.
For example, there is disclosed a structure in which, when one of the print head and the platen roller, to which the print head is pressed, of the printing device is moved from a printing operation position to a release position for removing the sheet material, the one of the print head and the platen roller and one of the movable blade and the stationary blade are moved together (see, Patent Document 1).
Further, for another related art sheet cutting device, there is disclosed a structure in which the movable blade is mounted onto a side of a support portion for supporting a platen roller, and when the platen roller is moved to the release position spaced apart from the print head, a press contact state between the movable blade and the stationary blade and connection between the movable blade and a drive mechanism for moving the movable blade are released, and with a removal of the sheet material being the obstacle for the operation of the movable blade, the movable blade returns to a cutting stand-by position spaced apart from the stationary blade (see, Patent Document 2).    [Patent Document 1] JP 2002-219832 A    [Patent Document 2] JP 2004-237555 A
As disclosed in Patent Document 1, in the structure in which the stationary blade moves together with the print head or the platen roller, there is a risk of the print head or the platen roller being moved before a release operation in which the movable blade is moved with respect to the stationary blade to the cutting stand-by position. Further, there is a risk of the print head or the platen roller impacting on the movable blade which has not been completely moved to the cutting stand-by position. In order to prevent the impact between the movable blade and the print head or the platen roller, it is necessary that a space for moving the movable blade completely to the cutting stand-by position, that is, a space for ensuring a time for moving the movable blade to the cutting stand-by position be provided in the device. Thus, there is a problem in that the device as a whole is upsized.
Further, as disclosed in Patent Document 1, in a case of the structure in which the stationary blade or the movable blade is integrally moved together with the print head or the platen roller, a moving direction in which the print head and the platen roller are spaced apart from each other is regulated, so there is a problem in that an opening and closing direction with respect to a device main body is limited.
In a structure disclosed in Patent Document 2, there is required a retaining mechanism for a movable blade unit, formed of a separate member such as a cover or the like for a casing, for example, and a cutting operation cannot be performed by the printer alone. Accordingly, in a device of an automatic sheet insertion mechanism type, which does not require attachment and detachment of the print head or the platen roller of a printing portion, there is a problem of upsizing the device as a whole.
Further, also in the device of the automatic sheet insertion mechanism type as described above, when the sheet material is removed at the time of the paper jam in the printer, it is necessary that the print head or the platen roller of the printing portion be detachable.